The aim of the study is to investigate the memory immune response and the yearly persistence of the immunity against Japanese Encephalitis (JE) after vaccination with a new Japanese Encephalitis Chimeric Virus (JE-CV) in participants previously vaccinated with JE-CV.

Objectives:

To describe JE immune status before, and after a JE-CV booster dose in subjects previously vaccinated with JE-CV

To describe the immune status before, and immune response following JE-CV vaccination in JE-naïve control subjects.

To describe the safety (in terms of solicited and unsolicited adverse events) of a single dose of JE-CV up to 6 months after the last vaccination.

To describe all related serious adverse events (SAEs) and related deaths from 6 months to 5 years after vaccination in JE-CV-primed subjects.

Note: Immunogenicity data on Japanese encephalitis chimeric vaccination will also be assessed on Day 7 post-vaccination for all participants and yearly for up to 5 years post-vaccination in Group 1 participants.

Secondary Outcome Measures:

Information concerning the safety in terms of solicited and unsolicited adverse events of the vaccination in JE CV recipients and varicella recipients, respectively. [ Time Frame: Day 0 to 6 months post-vaccination ] [ Designated as safety issue: No ]

Note: In Group 1 participants, solicited and unsolicited adverse events of the vaccination will also be reported yearly for up to 5 years post-vaccination.

Study participants who are previously immunized with Japanese Encephalitis Chimeric Virus (JE-CV) vaccine will receive a single dose of the new JE-CV and will be followed up for 5 years for immunogenicity.

The control (JE-CV naive) participants will receive either one dose of JE-CV or one dose of varicella vaccine.

All participants will be monitored for safety for 6 month post vaccination.

Eligibility

Ages Eligible for Study:

36 Months to 42 Months

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

Yes

Criteria

All Participants

Aged 36 to 42 months on the day of inclusion

Provision of Informed Consent Form signed by at least one parent or other legally acceptable representative.

Subject and parent/legally acceptable representative or guardian able to attend all scheduled visits and to comply with all trial procedures

In good general health, based on medical history and physical examination

For Japanese Encephalitis Chimeric Virus (JE-CV) vaccine primed group only

Subject who was vaccinated with JE-CV in JEC02 trial (NCT00735644)

History of central nervous system disorder or disease, including seizures and febrile seizures

Known systemic hypersensitivity to any of the vaccine components, or history of a life-threatening reaction to the vaccine used in the trial or to a vaccine containing any of the same substances

Chronic illness or any underlying illness (such as cardiovascular, kidney, liver or hematological disease or development abnormalities) that, in the opinion of the investigator, is at a stage where it might interfere with trial conduct or completion

For Japanese Encephalitis Chimeric Virus (JE-CV) primed participants only

Receipt of any Japanese Encephalitis (JE) vaccine other than JE-CV during JEC02 trial (NCT00735644) and since the end of JEC02 trial

For JE-CV naive participants only

Previous vaccination against flavivirus disease including JE

History of flavivirus infection either based on clinical suspicion or laboratory proven

Previous vaccination against varicella

Previous vaccination with JE-CV in JEC02 study

History of varicella, confirmed either clinically, serologically, or microbiologically

Known systemic hypersensitivity or anaphylactic/anaphylactoid reaction to neomycin.

Known history of thrombocytopenia or idiopathic thrombocytopenic purpura.

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01190228